Sewing machine



Aug. 1, 1933; o. F. HOPPE 1,920,643

SEWING MACHINE Filed Feb. 13,1951 Z'Sheets-Sheet 1 Aug. 1, 1933. I Q H PPE 1,920,643

SEWING MACHINE 'Filed Feb. 13, 1931 2 Sheets-Sheet 2 O 20 40 60 80 I I I I I 200 220 240 260 280 300 320 340 360 5 I @aw @Z Patented Aug. 1, 1933 OFFICE 1,920,643 SEWING MACHINE Otto F. Hoppe, Frankfort-on-the-Main, Ger many, assignor to United Shoe Machinery Corporation, Paterson, N.

Jersey J a Corporation of New Application February 13, 1931, Serial No. 515,500,

and in Great Britain February 25, 1930.

10 Claims.

The present invention relates to sewing machines, and more particularly to lockstitch shoe sewing machines having a curved hook needle.

Machines of this type, as usually heretofore 5 constructed, have been provided with a rotary or oscillating hook which casts the needle loop about a bobbin case, but in so doing imparts a half twist to the loop. Largely on account of the construction and arrangement of these shut- Lles or hooks, and of the mechanism for supporting and actuating them, and also on account of the friction and strain put upon the thread by these shuttles or hooks, and by the devices for I spreading the needle loop to facilitate the entrance of the shuttle or hook into the loop, the

speed atwhich it is practical to drive these machines is limited, and where attempts have been made to drive such machines at a comparatively high speed, breakage of thread and inferior stitch 2O formation has resulted as well as rapid wear of the parts and even the generation of a suflicient amount of heat to melt the wax on the bobbin thread or otherwise injure the thread.

r The present invention, therefore, has for one of its several objects, to provide a curved hook needle lockstitch machine which may be operated at a speed which is considerably higher than the speed usual in machines of this type, while avoiding rapid wear of the parts, abrasion or breaking 3 of the thread or injurious heating of'the bobbin thread.

Other objects of the invention are to provide a curved hook needle lockstitch machine having an improved construction and arrangement of parts for manipulating the needle and bobbin threads in order to interlock these threads in the formation of a lockstitch seam.

With the above objects in view, a feature of the present invention contemplates the provision in a curved hook needle lockstitch sewing machine of loop spreading fingers arranged to enter a needle loop and by relative movement of said fingers to spread the loop, together with a looptaking hook arranged to take the spread loop from the loop spreading fingers and cause the loop to be passed over a stationary bobbin case without itself, as a whole, passing through the loop.

Another feature of the invention contemplates the provision in a curved hook needle lockstitch sewing machine having a loop taking hook -arranged to move about a stationary bobbin case, of a loop engaging device arranged to engage a side of the loop at eachside of the bobbin :case

and force the loop in a direction to pass the bobbin case through the loop.

The features of invention above referred to andotherfeatures consisting of new and improved constructions and arrangements of parts will become fully apparent to those skilled inthe art from a'consideration of the following description given byway of example, and with reference to the accompanying drawings in a preferred form of mechanism according to theinvention which will be considered as being embodied ina .machine of that well-known type which is referred to in the shoe trade as the model 0 machine, and the general character ofwhich is -dis- 1 closed the patent to Ashworth No. 1,169,909 dated February 1, 1916.

In the drawings:

Figure 1 is a right-hand side elevation showing the preferred form of mechanism in its relation to some of the parts of a curved hooked needle loc'ks'titch machine of the above type;

Figure 2 is a front elevation of the said preferred form of mechanism and the said parts;

Figure 3 is aloft-hand side elevation showing some of the :said preferred form of mechanism; v

Figure 4' shows to an enlarged scale a bobbin case, in section, andthread handling devices of the said mechanism in f-ront'elevation;

Figure 5' is a side elevationof certain of the thread handling devices shown in Figure 4; and

.Fig-ure 6 is a diagram showing the relative timing of the thread handling devices of the said preferred form of mechanism and the timing of someof the devices ofa curved hooked needle lockstitch machine of the type referred to.

In the accompanying drawings there are shown a' work support 1, a. presser foot 2, an awl 3, a needle 4, a thread finger [5 and a looper 6 of a curved hooked needle lockstitch machine of the V type referred to.

' In the' said preferred form of mechanism the shuttle or rotary hook is abolished and there is simply a substantially stationary bobbin case '7 containing the bobbin 8, the loop of thread i drawn up by the needle being taken from the needle and passed roundthe bobbin case 7 'by' reciprocatory loop handling devices. The bob bin case '7 ispositioned at the left of the needle 4 viewing the machine from the front and above lot the axis of the curve of the needle, the axisof the bobbin 8 extending horizontally forwardly and rearwardly of the machine. The discoidal bobbin case 7, has at the top left hand side of it an' opening through which an empty bobbin' maylbe removed and a full one inserted without chine.

removing the bobbin case from the machine or loosening or removing any parts. Fixed to the inside of the casing 7 is a bobbin thread tension spring 9 which presses the bobbin thread against a wall 10 on the case. The spring 9 is cut away at one side as shown at 11 (Figure 1) to provide an opening into the bobbin case through which a tool may be inserted to raise the empty bobbin for removal and through which the bobbin thread may be readily passed and then placed between the spring 9 and wall 10, there being at the bottom of the spring a small thread guiding and controlling notch 12. The bobbin case 7 is supported by a bracket 13 extending forwardly from the machine frame and is held in position in a slot 16 in the bracket by a slotted vertical plate 14, slidingly mounted on the bracket 13, which straddles the bobbin case and enters vertical grooves formed in the front and rear walls of the case. The slot '16 in the bracket which receives the case is somewhat larger than the latter to allow of the loop of thread being passed-round the case and the latter rests on the bracket 13 at the bottom of the slot 16.

The loop of thread drawn up by the needle is engaged by a pair of fingers 17, 18 which engage that side of the loop which leads to the thread supply. The fingers as they are raised to carry the loop into position to be passed around the bobbin case 7 are separated to open the loop. The fingers are carried by an arm 19 extending forwardly and rearwardly of the machine, which is pivotally mounted at its rear end on a shaft 29 fixed in the frame of the machine and extending horizontally across the machine. The arm 19 is pivotally connected to one end of a link 21, the other end of which is provided with a square opening 22 which surrounds a cam 23 on a countershaft 24 of the machine geared to and therefore driven in time relation to the cam shaft of the machine. By this means the fingers 17, 18 aregiven an up and down movement about the pivot of their arm, there being a dwell at each end of the movement; The fingers 17, 18 are arranged one behind the other and have at their lower ends hooks which enter the loop. The rear finger 18 is fixed in the arm and the front finger 17 is fixed on one end of a stud 25 rotatably mounted in the end of the arm 19 and extending horizontally across the ma The other end of the stud 25 has fixed on it'an upwardly extending short arm 26 the upper end of which is pivotally connected to a rearwardly and downwardly extending link 27.

4 The rear end of this link 27 is pivotedto the frame of the machine at 29 a little below and in front of the pivot 20 of the finger-carrying arm. The hooks on the lower ends of the fingers 17, 18 are swung, in each cycle of the machine,

" from a position just below the needle point,

when it is in its retracted position, and behind the needle loop drawn up by the needle, to a position about level with the top of the bobbin case.

close to the rear finger 18 their hooks being then more or less in contact and when the arm 19 is in its highest position the lower ends of the'fingers (or the hooks) are separated about three-quarters of an inch. The fingers'in effect I Since the'finger carrying arm 19 and the. F link 27 connected to the movable finger 17 swing engage the needle loop and act on it much in the manner of the usual loop spreader of said model 0 machine but owing to their separating movement they spread it so that when in their raised position the loop extends fromthe work in the form of a four-sided loop; that is one straight legof thread 30 (Figure 5) coming from the thread supply extends from the work to the hook of the forward finger 17, amoreor less horizontal straight leg of thread 31 extends rearward therefrom to the rear hook 18, a straight leg of thread 32 extends from the latter hook downwardly and rearwardly to the needle hook 4 and the thread then returns to the work forwardly and downwardly from the needle hook.

The rearwardly extending portion 31 of the loop of thread that is between the'hooks17, 18 is engaged by a hook 33 formed on a loop-taker 34 which advances from the left-hand side of the bobbin case 7 through the slots in the bobbin-case carrying bracket 13 and slide 14, hereinbefore referred to, over the top of the case and over the top of the thread between the hooks 17, 18 so that the hook 33 formed on its under side engages this section 31 of the thread as this loop taker retires. The loop-taker consists of a thin metal strip about three-eighths of an inch wide which is curved somewhat so as to pass closely over and partly around the case 7 and has at its outer end the hook 33 referred to and a projecting tongue 60 to guide the thread by its under face (the left hand face in Fig. 4) to the hook 33 as the fingers 17, 18 approach their fully. raised position with the portion 31 of the thread extending between them. The strip at its other end is fixed to a gear. segment 35 which is rotatably mounted on a stud 36 fixed in the forward end of an arm 37 which is pivotally mounted on the machine frame on a horizontal shaft 38 extending across the machine. Projecting upwardly from the hub of the segment carrying arm 37 is a short-arm 39 which is pivotally connected'to one end of a'link 40 the other end of which has in it a, square opening to receive a cam on the said countershaft 24 of the machine by which cam the segment arm is oscillated upwardly and downward 1y there being a dwell at each end of its stroke. As the segment is carried up and down by said arm 37 it travels over a fixed rack 41 and is thereby oscillated on its pivot stud. The effect of these movements of the gear segment is that the hooked end of the loop-taker 34 is carried, as the segment 35 moves up, from a position at the left of the case which is about level with the axis of the bobbin up and over the case to a position where the hook can receive the thread extending between the hooks of the fingers 17, 18 and as the segment 35 moves down the hooked end of the loop-taker moves back to its origi-. nal position takingwith it, in the hook 33 on its under side, the needle loop and passing it over the top of the case 7. The rack 41 is formed on a block 42 which is fixed by screws 43 to the bracket 13 and the arm 37 has fixed to it a plate 44 which engages a face on the block and prevents the segment 35 from moving away from the rack.

The vertical slide 14 hereinbefore referred to as having in it a slot which straddles the case 7 and as entering grooves 15 at the front and rear of the case acts as indicated below to pass the slot in the plate a shallow notch or recess hook, and drawn under the 45. The notches 45, when the loop 'of thread is drawn by the loop taker over the top of the case, are just above the case and receive the sides of the; loop and thereafter the slide 14, is moved down to carry in its notches the loop of thread'down round the case. The notches 45 are deep enough to allow thetthread to pass at the back and front ofthe case between the slide and the case, and as the slide holding the loop descends and the loop is drawn down it is drawn from the hook on the loop taker 34. The slide 14 has pivoted to it near its upper end on a horizontalstud etxending across the machine the-lower end of a toggle link 46 which extends rearwardlyand upwardly and pivotally connected to a second toggle link 47. 0nd link 47' extends forwardly and upwardly and is pivoted at 48. to the bobbin-case carrying bracket 13 above the pivot of the first link 46. Pivotally connected to the toggle joint is a rearwardly extending rod 49 the rear end of which is pivotally connected to the upper end of a substantially'vertical arm 50 which is pivoted on a horizontal stud 51 extending across the machine and fixed in the aforesaid bracket. Pivotally connected tothe arm 50- about mid-way of its length is a rearwardly extendinglink 52 having in its rear end a square opening which embraces a cam on the shaft 24'and by, which the toggle is operated to move the slide up and down at the appropriate times in. the machine cycle.

When the loop-taker 34 has operated to draw the loop oil the, hooks of the fingers 17, 18 and the needle barb and over the top or the bobbin case 7 and the notched slide 14 passed the sides of the loop down the bobbin case the operation of the takeup acts to draw theloop back through the slots in the bobbin-case bracket 13 and slide 14 and beneath the case and into the Work, the case 7 being slightly lifted from the bottom of the slot in the bracket by the thread as it passes under the case. A block 54 fixed to the bracket 13 prevents the bobbin case from lifting unduly.

- -As the fingers are raised they separate and carry the thread extending between their hooks under the tongueon the loop-taker and above the looptaker hook 33 (as shown in Figs. 4 and 5) so that the hook as it moves back engages the thread and draws the loop over the top of the bobbin case, the sides of the loop entering the recesses 45 in the slot in the vertical plate 14. The plate 14 moves down to carry the loop down around the case and the loop is stripped from the loop taker bobbin case by the takemp which operates in the usual manner to draw the loop and set the stitch.

The times in a single cycle or" the machine at which the needle, the take-ups, the fingers 17, 18, the loop-taker 8'4 and the slide 14 operate will now be described. The starting or zero point in the cycle will be taken chine is automatically stopped when the clutch treadle released and the points in the cycle at which the movements of the various devices com- -,arated at zero lse'e B Figure 6).

The secspeed.

as that at which the ma mence andfinish twill -be given in degrees of rotation of the count-e'rsha'fit 24 or the main cam shaft of the machine which rotate at the same speed. l i a The needle at the zero position "(see A Figure 6) is part way back. "It is fully back at and immediately begins to move forward. It is fully forward at 130 and immediately begins to move It isfully back'at 240 and immediately begins-to move forwardagain. It stops partway down at 330 and immediately begins to move back and is part 'way backat 360.

The fingers 17, 1-8 are fully raised and sep- They immediately begin to move down and close when the machine is started. They are fully down and closed at where they dwell until 180. They then begin to move up and separate and reach their Euppermost and fully separated position at 310. V 'y The loop-taker 34 at the zero position (see 0 Figure 6) is at the left of the bobbin case and fully down. It commences to move'up and over down when the machine is started reaching its no is fully raised at 295 and then fallstill lowest position at rise and The auxiliary take-'up'at the Zero positionis up (seeF Figure 6) It remains up till 10 when it begins tofall; It reaches its lowest position at 135 where itdwells until 190. 'It then moves up until 260 when it begins tomove part-way down again.- It stopsthis movement at 300 and then rises to its fully up position 335. 1

With a mechanism such as is above described, for passing the loop of thread drawn up by the needle over the bobbin case, rotation or oscillation of any somewhat heavy shuttle of the usual kind and the parts for operating such a shuttle are dispensed with and the parts as above described for passing the loop over the case can be of a very light construction-and be operated at high It immediately. begins to The invention having been described, what is claimed is: a x

1. In a sewing machine, the combination with a curved hook needle of a stationary bobbin case, a loop spreader comprising two fingers, means for moving the fingers to cause them to engage the needle loop and for moving them relatively to each other to spreadthe loop, a loop taker com prising a hook, and means for actuating the loop taker to cause its hook to take the loop from the fingers and move about the bobbin case.

2. In a sewing machine, the combination with a curved hook needle of a stationary bobbin case, a loop spreader comprising two fingers, means for moving the fingers to engage the needle loop while stretched between the work and the needle hook and for moving them relatively to each other to spread the loop, a loop taker-comprising a hook, andmeans for actuating theloop taker to cause its hook to take the loop from the fingers and move. about the bobbin case.

3. In a sewing machine the combination with a curved hook needle of a stationary bobbin case and means for passing a needle loop over the bobbin case comprising two loop spreading fingers, a carrier upon which the fingers are mounted, means for moving the carrier to cause the fingers to engage the needle loop, and means for -moving one finger relatively to the other on the carrier to spread the loop.

4. In a sewing machine, the combination with a curved hook needle of a stationary bobbin case, two loop spreading fingers, a pivoted arm upon which said fingers are mounted, means for moving the arm to cause the fingers to engage the needle loop, and means actuated bythe movement of the arm for moving the fingers relatively to eachother to spread the loop.

5. In a sewing machine, the combination with a curved hook needle of a stationary bobbin case and means for passing the needle loop over the bobbin case comprising two loop spreading fingers, a pivoted arm upon which one finger is rigidly mounted and upon which the other fingeris pivotally mounted, a link pivotally mounted at one end eccentrically to the pivot of the arm and connected at its other end to the pivotally mounted finger, and means for moving the arm to cause the fingers to engage the needle loop and to cause the pivotally mounted finger to move relatively to the other finger to spread the loop. 7

6. In a sewing machine, the combination with a curved hook needle of a stationary bobbin case and means for interlocking the needle and bobbin threads comprising a loop taking hook, means for actuating the hook to engage the needle loop and move about the bobbin case, a loop engaging device, and means for actuating the loop engaging device to engage a side .of the loop at each side of the bobbin case and force the loop in a direction to pass the bobbin case through the loop.

7. In a sewing machine, the combination with a curved hook needle of a stationary 'discoidal bobbin case having an opening in its peripheral edge to permit the insertion and removal of a the needle loop to carry the loop about the bobbin case.

8. In a sewing machine, the combination with a curved hook needleof a stationary bobbin case, means for supporting the bobbin case comprising a slide slotted to receive the bobbin case and engaging grooves in opposite faces of the bobbin case, said slide being provided with a notch at each side of the bobbin case to receive the needle loop while the loop is passing over the bobbin case, and means for interlocking the needle and shuttle threads comprising a hook, means for actuating the hook to engage the needle loop and move about the bobbin case, and means for actuating the slide to force the loop in a direction to pass the bobbin case through the loop.

9. In a sewing machine, the combination with a curved hook needle of a stationary 'discoidal bobbin case and means for interlocking the needle and bobbin threads comprising a hook, a carrier for the hook, an arm on which the carrier is rotatably mounted, and means for movin the arm and simultaneously rotating the carrier to cause the hook to move in a substantially circular path about the bobbin case.

10. In a sewing machine, the combination with a curved hook needle of a stationary discoidal bobbin case, means for interlocking the needle and bobbin threads comprising a hook, a carrier for the hook provided with a gear segment, an arm on which the carrier is rotatably mounted, a fixed rack engaging the gear segment, and means for actuating the arm to move the carrier along the rack, and thereby cause the hook to move in a substantially circular path about the bobbin case.

OTTO F. HOPPE. I 

